Wireless communication method and system for configuring radio access bearers for enhanced uplink services

ABSTRACT

A wireless communication method and system for controlling an enhanced uplink (EU) radio access bearer (RAB). The wireless communication system includes at least one wireless transmit/receive unit (WTRU), at least one Node-B and a radio network controller (RNC). The RNC configures an EU RAB to operate on an enhanced dedicated channel (E-DCH). At least one of the WTRU and the Node-B report EU traffic statistics and EU performance statistics to the RNC. The RNC then adjusts the configuration of the EU RAB in accordance with the received EU traffic statistics, the EU performance statistics, and information collected by the RNC itself.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/115,999 filed on Apr. 27, 2005, which claims the benefit of U.S.Provisional Application No. 60/566,458 filed on Apr. 29, 2004, which isincorporated by reference herein as if fully set forth. This applicationis also related to U.S. patent application Ser. No. 11/116,073 filed onApr. 27, 2005, which is incorporated by reference herein as if fully setforth.

FIELD OF INVENTION

The present invention is related to a wireless communication systemincluding at least one wireless transmit/receive unit (WTRU), a leastone Node-B and a radio network controller (RNC). More particularly, thepresent invention is a method and system for configuring enhanced uplink(EU) radio access bearers (RABs) for supporting EU services in thewireless communication system.

BACKGROUND

Methods for improving uplink (UL) coverage, throughput and transmissionlatency are currently being investigated in the 3rd generationpartnership project (3GPP). In order to achieve these goals, control,(i.e., scheduling and assigning), of UL resources, (i.e., physicalchannels), will be moved from the RNC to the Node-B.

The Node-B can make decisions and manage uplink radio resources on ashort-term basis more efficiently than the RNC. However, the RNC shouldretain coarse overall control of the EU RAB in terms of an allowedtransport format combination set (TFCS), maximum allowed transmit power,or the like.

SUMMARY

The present invention is related to a wireless communication method andsystem for controlling an EU RAB. The wireless communication systemincludes at least one WTRU, at least one Node-B and an RNC. The RNCconfigures an EU RAB to operate on an enhanced dedicated channel(E-DCH). At least one of the WTRU and the Node-B report EU trafficstatistics and EU performance statistics to the RNC. The RNC thenadjusts the configuration of the EU RAB in accordance with the receivedEU traffic statistics and the EU performance statistics.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding of the invention may be had from thefollowing description of a preferred embodiment, given by way of exampleand to be understood in conjunction with the accompanying drawingwherein:

FIG. 1 is a block diagram of a wireless communication system configuredin accordance with the present invention; and

FIG. 2 is a signal diagram of a process implemented in the system ofFIG. 1 for configuring an EU RAB.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereafter, the terminology “WTRU” includes but is not limited to a userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, or any other type of device capable of operating in a wirelessenvironment. When referred to hereafter, the terminology “Node-B”includes but is not limited to a base station, a site controller, anaccess point or any other type of interfacing device in a wirelessenvironment.

The features of the present invention may be incorporated into anintegrated circuit (IC) or be configured in a circuit comprising amultitude of interconnecting components.

FIG. 1 is a block diagram of a wireless communication system 100configured in accordance with the present invention. The system 100includes at least one WTRU 102, at least one Node-B 104 and an RNC 106.An E-DCH 108, (along with associated signaling channels), is establishedbetween the WTRU 102 and the Node-B 104, in addition to a regulardedicated channel (DCH) 110. Of course, those of skill in the art wouldunderstand that FIG. 1 does not depict all of the signaling, such as anydownlink (DL) channels, between the WTRU 102 and the Node-B 104 that isnot specifically relevant to the present invention.

The RNC 106 retains overall control of EU RAB via an Iub/Iur interface112. By properly setting the EU RAB parameters, the RNC 106 can keepcoarse control of the EU RAB and radio resources will be efficientlyutilized for both regular DCHs 110 and E-DCHs 108. The RNC 106 controlsthe EU RAB without closely monitoring EU transmissions from the WTRU 102to the Node-B 104 sent over an E-DCH 108 on a transmission time interval(TTI) basis.

When the RAB is configured to transfer E-DCH data, the RNC 106establishes configuration of EU services for the RAB by establishingWTRU configuration requirements. The initial configuration for each WTRU102 supporting the EU services may include, but is not limited to, atleast one of an allowed transport format combination set (TFCS) forE-DCH, allowed modulation and coding schemes (MCSs) for E-DCH, a maximumallowed E-DCH transmit power and a maximum allowed WTRU transmit power.The maximum allowed WTRU transmit power limits the sum of transmit poweron a regular DCH, an E-DCH, an uplink signaling channel for high speeddownlink packet access (HSDPA) and an uplink signaling channel forE-DCH.

The RAB may be configured using at least one of a channel allocationrequest response timer, (which defines a time limit for a Node-B toprovide an E-DCH allocation information before the WTRU generatesanother periodic channel allocation request), a block error rate (BLER)of an E-DCH transport channel (TrCH), a signal-to-interference ratio(SIR) of the E-DCH TrCH, mapping of medium access control for DCH(MAC-d) flows to an E-DCH TrCH, a maximum number of automatic repeatrequest (ARQ) retransmissions (preferably per MAC-d flow), a maximumnumber of hybrid-ARQ (H-ARQ) retransmissions, and a data lifespan timer,(defining a time limit for expiration of transmission of the E-DCHdata), within a WTRU MAC for EU (MAC-e) and a physical layer for EU(PHY-e) for each TrCH. The WTRU MAC-e may discard the E-DCH data whenthe maximum number of H-ARQ retransmissions is exceeded or when thelifespan timer expires.

Initially, the allowed TFCS and MCSs for E-DCH are configured byconsidering at least one of the current load of regular DCH traffic inthe UL of a cell, current load of EU traffic in a cell, and informationof the WTRU 102 to be configured for EU services. The current load ofregular DCH traffic in the uplink of a cell is determined by at leastone of resource usage, average transmit power, average interference, arequired energy per bit to noise ratio, a data rate, and an activityfactor. The current load of EU traffic in a cell is determined by atleast one of resource usage, average transmit power, averageinterference, possible MCS, average probability that each MCS isapplied, a required energy per bit to noise ratio of each MCS, possibleTFCs and average probability that each TFC may be applied, and anactivity factor. Information of the WTRU 102 to be configured for EUservices includes information of its current regular DCH, (a data rate,a required energy per bit to noise ratio and an activity factor onregular DCH), and information of expected E-DCH, (expected data rate ofthe EU services, QoS (such as block error rate), activity factor, or thelike.

The maximum allowed transmit power of the WTRU 102 should be configuredbecause EU service is added to the RAB that currently has regular DCHs.The maximum allowed E-DCH transmit power and maximum allowed WTRUtransmit power are determined by considering the same factors for theallowed TFCS and MCS with some additional factors, such as currentmaximum allowed WTRU transmit power configured by the RNC 106, and thenumber of events that maximum transmit power is reached.

Parameters such as maximum number of H-ARQ/ARQ retransmissions, alifespan timer, or the like, are determined based on the QoS of RABsmapped to the MAC-d flow. The maximum H-ARQ retransmissions and WTRUMAC-e transmission lifespan are determined by considering maximumallowed transmission latency and BLER requirements to maintain QoS.MAC-d flows occur between logical channels and transport channels of theWTRU 102, which are used to establish the parameters of the EU RAB.

Each MAC-d flow has unique configurable parameters that relate to arequired QoS for the RABs. The WTRU 102 and the Node-B 104 may beconfigured by the RNC 106 to multiplex a plurality of MAC-d flows on anE-DCH TrCH. Scheduling priority may be given to one MAC-d flow overanother MAC-d flow. This may be accomplished by an absolute prioritymechanism where transmission of higher priority data is alwaysmaximized. At least one of allowed transport formats (TFs), MCSs,transmit power, BLER, MAC for DCH (MAC-d) flow mapping, maximum numberof H-ARQ/ARQ retransmissions and data lifespan parameters may be uniquefor each MAC-d flow.

Scheduled EU transmissions can only use TFCS and MCSs that are allowedin the configuration. The transmit power on E-DCH should not exceed themaximum allowed E-DCH transmit power configured by the RNC 106. The sumof transmit power on a regular DCH and an E-DCH should not exceed themaximum allowed WTRU transmit power configured.

The transmissions of the WTRU 102 on the E-DCH 108 are also subject tothe constraint of the parameters configured for the E-DCH TrCH, (e.g., alifespan timer, a maximum number of H-ARQ retransmissions, a number ofARQ retransmissions, or the like). If the maximum number of H-ARQprocess transmissions or the transmission lifespan timer is exceeded,the WTRU MAC-e may discard the transmission and initiate service of thenext transmission from higher layers.

Once the WTRU 102 starts to operate on the E-DCH 108, EU trafficstatistics and performance statistics are reported to the RNC 106 foreach MAC-d flow or TrCH mapped to the EU RAB. The EU traffic statisticsinclude traffic volume measurement (TVM) of EU data stored in the WTRU102, and volume of successful or unsuccessful EU data transmissionswhich occur over a predetermined time period. The EU performancestatistics include at least one of resource utilization per cell,resource utilization per WTRU, an ACK/NACK ratio per cell, an ACK/NACKratio per resource, an ACK/NACK ratio per WTRU, average number oftransmissions that failed in the medium access control (MAC) layer, (oraverage number of transmissions that failed in the MAC layer), averagechannel quality indicator (CQI) results per cell, average CQI resultsper resource, average CQI per WTRU, best CQI results, worst CQI results,the number of events for which WTRU maximum transmit power is reached,the number events for which EU maximum transmit power of the WTRU isreached, the number of transmission failures due to hybrid-automaticrepeat request (H-ARQ) process retransmission limit, and the number oftransmission failures due to EU transmission lifespan timeout,

EU traffic and performance statistics may be reported from the WTRU 102and the Node-B 104 to the RNC 106. The report from the WTRU 102 may berelayed by the Node-B 104 to the RNC 106. The reporting can be periodicor threshold based. The periods or thresholds of reporting are set bythe RNC 106 and are also design parameters.

In the case that EU traffic and performance statistics are reported onlyby the Node-B 104 to the RNC 106, the EU traffic and performancestatistics that are collected by the WTRU 102 are reported to the Node-B104 through a physical or MAC layer signaling. If EU traffic andperformance statistics are forwarded to the Node-B 104 from the WTRU 102using physical or MAC layer signaling, they can be collected andforwarded to the RNC 106 via the Iub/Iur interface 112.

Other measurement data known only to the Node-B 104 can also be sent tothe RNC 106 to allow for the RNC 106 to control EU resources. Thisincludes received code power on EU assigned codes reported on a WTRU orcell basis, interference received based on EU assigned codes, and anACK/NACK ratio as perceived by the Node-B 104.

In addition to EU traffic and performance statistics and measurementreports sent to the RNC 106, the adjustment of configuration of EUservices also depends on some information that are collected by the RNC106 itself, which includes traffic and performance statistics of aregular DCH 110 and some EU performance statistics.

Upon receiving the reported EU traffic and performance statistics andmeasurement reports from the WTRU 102 and/or the Node-B 104, the RNC 106adjusts configuration of the EU RAB, such as allowed TFs, MCSs, transmitpower, BLER, MAC-d flow mapping, H-ARQ retransmission and data lifespanparameters for each MAC-d flow or TrCH according to the reported trafficand performance statistics. In this way, the RNC 106 keeps coarsecontrol of the EU RAB.

FIG. 2 is a signal diagram of a process 200 implemented in the system100 for configuring and reconfiguring EU RABs in accordance with thepresent invention. The method is implemented between at least one WTRU102, at least one Node-B 104 and an RNC 106. The RNC 106 sends initialconfiguration parameters, (e.g., channelization codes, maximuminterference, maximum allowed TFCS/MCSs, a maximum allowed E-DCH andWTRU power, or the like), for the Node-B 104 through the Iub/Iurinterface 112 (step 202). The RNC 106 configures an EU RAB by systemconfiguration parameters, (e.g., maximum allowed TFCS/MCSs, maximumallowed E-DCH and WTRU power, the maximum number of H-ARQ transmissions,a data lifespan timer, a channel allocation response timer for periodicchannel allocation request generation, or the like), to the WTRU 102through radio resource control (RRC) messages when the EU RAB isconfigured to operate on the E-DCH 108 (step 204). EU scheduling isperformed by the Node-B 104 within the limits of the configuration setby the RNC 106 and transmitted by physical or MAC layer signaling (step206). The WTRU 102 reports EU traffic and performance statistics, (e.g.,TVM, amount of transmit (TX) data, an ACK/NACK ratio, a channel qualityindicator (CQI), and the number of maximum power events, or the like),to the RNC 106 through RRC messages (step 208), or to the Node-B 104 byphysical or MAC layer signaling (step 210) to be forwarded to the RNC106 via the Iub/Iur interface 112 (step 212). The RNC 106 reconfiguresthe EU services and the EU RAB in accordance with the reportedstatistics (step 202).

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the preferred embodiments or in various combinations with orwithout other features and elements of the present invention.

What is claimed is:
 1. A method for controlling enhanced uplink (EU)transmission, implemented by a Node B, comprising: receiving, by a NodeB, configuration information from a radio network controller (RNC), theconfiguration information including a maximum number of retransmissionsassociated with each of a plurality of medium access control fordedicated channel (MAC-d) flows for an EU channel; and transmittingperformance information to the RNC, the performance informationindicating that the maximum number of retransmissions associated withone of the plurality of MAC-d flows is exceeded.
 2. The method of claim1 wherein the EU channel is an enhanced dedicated channel (E-DCH)between a wireless transmit/receive unit (WTRU) and the Node B.
 3. ANode B for controlling enhanced uplink (EU) transmission comprising:circuitry configured to receive configuration information from a radionetwork controller (RNC), the configuration information including amaximum number of retransmissions associated with each of a plurality ofmedium access control for dedicated channel (MAC-d) flows for an EUchannel; and circuitry configured to transmit performance information tothe RNC, the performance information indicating that the maximum numberof retransmissions associated with one of the plurality of MAC-d flowsis exceeded.
 4. The Node B of claim 3 wherein the EU channel is anenhanced dedicated channel (E-DCH) between a wireless transmit/receiveunit (WTRU) and the Node B.
 5. A method to configure a wirelesstransmit/receive unit (WTRU) to support enhanced uplink (EU) services,implemented by a WTRU, comprising: receiving at least one control signalfor configuring the WTRU; configuring a maximum number of hybridautomatic repeat request (H-ARQ) transmissions for each of a pluralityof medium access control (MAC) for dedicated channel (MAC-d) flows basedon the at least one control signal; multiplexing at least one of theplurality of MAC-d flows for transmission over an enhanced uplinkchannel; selecting one maximum number of H-ARQ transmissions to use fortransmission of the multiplexed MAC-d flows, wherein the one maximumnumber of H-ARQ transmissions is selected based on the maximum number ofH-ARQ transmissions associated with each of the MAC-d flows that aremultiplexed; transmitting the multiplexed MAC-d flows over the enhanceduplink channel; and stopping re-transmission of the multiplexed MAC-dflows on a condition that the one maximum number of H-ARQ transmissionsis exceeded.
 6. The method of claim 5, further comprising: reporting EUtraffic statistics, wherein the EU traffic statistics include a volumeof EU data; receiving a further control signal in response to thereported EU traffic statistics; and configuring the WTRU based on thereceived further control signal.
 7. The method of claim 5, furthercomprising: generating periodic channel allocation requests to transmitE-DCH data.
 8. The method of claim 5 wherein the at least one controlsignal includes a maximum allowed transmit power.
 9. The method of claim5 wherein the at least one control signal is received via radio resourcecontrol (RRC) signaling.
 10. The method of claim 5 wherein the at leastone control signal is received from a radio network controller (RNC).11. The method of claim 5 wherein the maximum number of H-ARQtransmissions for each of the plurality of MAC-d flows is associatedwith a quality of service (QoS).
 12. A wireless transmit/receive unit(WTRU) configured to support enhanced uplink (EU) services comprising:circuitry configured to receive at least one control signal forconfiguring the WTRU; circuitry configured to configure a maximum numberof hybrid automatic repeat request (H-ARQ) transmissions for each of aplurality of medium access control (MAC) for dedicated channel (MAC-d)flows based on the at least one control signal; circuitry configured tomultiplex at least one of the plurality of MAC-d flows for transmissionover an enhanced uplink channel; circuitry configured to select onemaximum number of H-ARQ transmissions to use for transmission of themultiplexed MAC-d flows, wherein the one maximum number of H-ARQtransmissions is selected based on the maximum number of H-ARQtransmissions associated with each of the MAC-d flows that aremultiplexed; circuitry configured to transmit the multiplexed MAC-dflows over the enhanced uplink channel; and circuitry configured to stopa re-transmission of the multiplexed MAC-d flows on a condition that theone maximum number of H-ARQ transmissions is exceeded.
 13. The WTRU ofclaim 12, further comprising: circuitry configured to report EU trafficstatistics, wherein the EU traffic statistics include a volume of EUdata; circuitry configured to receive a further control signal inresponse to the reported EU traffic statistics; and circuitry configuredto configure the WTRU based on the received further control signal. 14.The WTRU of claim 12, further comprising: circuitry configured togenerate periodic channel allocation requests to transmit E-DCH data.15. The WTRU of claim 12 wherein the at least one control signalincludes a maximum allowed transmit power.
 16. The WTRU of claim 12wherein the at least one control signal is received via radio resourcecontrol (RRC) signaling.
 17. The WTRU of claim 12 wherein the at leastone control signal is received from a radio network controller (RNC).18. The WTRU of claim 12 wherein the maximum number of H-ARQtransmissions for each of the plurality of MAC-d flows is associatedwith a quality of service (QoS).